(NBC NEWS) -- Skywatchers in the eastern United States have an opportunity to spot the launch of the SpaceX Falcon 9 rocket on an International Space Station resupply flight on Sunday night, weather permitting.
The night launch will mark the fourth flight of SpaceX's Falcon 9 rocket, a privately built booster that has made three successful flights since 2010. The rocket will be carrying the gumdrop-shaped Dragon capsule to the International Space Station. In May the Dragon capsule became the first U.S. spacecraft to reach the space station since NASA's last space shuttle flight departed in July 2011.
To reach the space station, the Falcon 9 rocket must be launched when Earth's rotation carries the launch pad into the plane of the station's orbit. That will happen on Sunday at 8:35 p.m. EDT at Launch Complex 40, SpaceX's launch pad at the Cape Canaveral Air Force Station in Florida.
As has been the case with space shuttle launches to the space station, Sunday's liftoff will bring the Falcon 9 rocket's path nearly parallel to the U.S. East Coast. It is expected that the glow created by the rocket's Merlin 1C liquid propellant rocket engines should be visible in varying degrees along much of the Eastern seaboard.
The Falcon 9 rocket launches into orbit using two stages. The first stage utilizes nine Merlin 1C engines which will burn for three minutes, then shuts down. Five seconds later the first and second stages will separate.
Seven seconds later the second stage, which utilizes just one engine will be fired and will burn for six minutes and two seconds. The Dragon space capsule will then separate from the second stage and head into orbit.
So while the first stage should create a fairly conspicuous bright light in the sky, the second stage will likely be considerably dimmer.
Kevin Fetter, a well-known amateur satellite observer based in Canada, notes:
"The first stage from what I see is very bright source of light. The second stage won't be as good for causing a light show. So once the first stage is done, the nice light show is over. The light coming from the second stage won't be as bright, so not everyone will have a nice view."
What to expect
In the southeast United States, depending on a observer's distance from Cape Canaveral, the Falcon 9 rocketshould be readily visible thanks to the fiery output of the nine Merlin 1C engines powering the first stage. The light emitted will be visible for the first three minutes of the launch out to a radius of about 500 miles from Cape Canaveral — an area more than three times the size of Texas.
Veteran satellite watcher, George William Herbert said: "It won't be the same as the shuttle, which is much, MUCH bigger and whose [solid rocket boosters] have hot glowing white aluminum oxide in the exhaust and smoke trail. However, the Falcon 9 engines burn kerosene and liquid oxygen, (which) are pretty bright, and will be brighter than an Atlas launch, which would be the closest comparison."
Another veteran satellite watcher, Richard Langley of Florida said: "I saw the 22 May launch from Marco Island (about 170 miles from Cape Canaveral). Only an extended red dot nears the horizon, but neat all the same."
Depending on where you are located relative to Cape Canaveral, Falcon 9 might become visible anywhere from just a few seconds up to perhaps three minutes after it leaves Complex 40 at 8:35 p.m. EDT on Sunday.
After the first stage is shut down, Falcon 9 will be visible only by virtue of the light emanating from its second stage thanks to a single Merlin 1C engine. It should appear as a small, pulsating, fast-moving star, shining with a yellowish-orange glow.
However, those who remember sighting the brilliant glow of the space shuttle as it raced along the Atlantic seaboard on its way to orbit, may be disappointed in their attempt to sight Falcon 9, whose single engine fires with only a fraction of the brilliance of the three main engines of the shuttle.
Still, it might be worth the attempt to try and see what might be seen. As the old saying goes: Nothing ventured, nothing gained.